Effects of Ageing on the Immune System: Infants to Elderly.

Physiological ageing is accompanied by decline in immune system function and immune alteration during ageing increases susceptibility to infections. We retrospectively analysed the data for complete blood count (CBC) and lymphocyte subsets from infant to elderly age groups to determine changes during ageing. Data from dual-platform flow cytometry and CBC were analysed to determine the percentage (%) and absolute cell counts (Abs) of peripheral blood lymphocyte subsets (CD3, CD4, CD8, CD19 and CD56+16+ cells) in infants (1 month to 1 year), children (1 year to 6 years), adolescents (12 years to 18 years), adults (21 years to 50) and elderly (70 years to 92 years). Differences in plasma cytokine levels in adults and elderly were also analysed using Randox system. Comparisons among age groups from infants through adults revealed progressive declines in the percentage of total lymphocytes and absolute numbers of T and B cells. The NK cells declined from infancy to adulthood but increased in elderly participants. The percentages of T cells increased with age from infant to adulthood and then declined. Pro-inflammatory cytokines, TNF-α and IL-6, were higher in elderly people compared to adults. The elderly group had significantly higher levels of monocyte chemoattractant protein-1 (MCP-1) and lower levels of epidermal growth factor (EGF) compared to adults. Our findings confirm and extend earlier reports on age-related changes in lymphocyte subpopulations and data generated from this study is useful for clinicians and researchers, patient management in various age groups for the interpretation of disease-related changes, as well as therapy-dependent alterations.

Influence of 4- and 6-color flow cytometers and acquisition/analysis softwares on the determination of lymphocyte subsets in HIV infection.

BACKGROUND AND OBJECTIVES: Lymphocyte immunophenotyping provides valuable information for the diagnosis and monitoring of patients with cellular immunodeficiencies, such as HIV/AIDS. In this study, we have assessed the influence of 4-color and 6-color flow cytometers, and respective analytical softwares on the enumeration of lymphocytes in HIV infected individuals. METHODS: The expression of various cell surface markers on lymphocytes was measured from the EDTA blood of 66 HIV infected patients on the FACSCalibur (4-color) and FACSCanto (6-color) flow cytometers. Percentage of lymphocytes expressing a particular cell surface marker was analyzed on FACSCalibur using the Cell Quest Pro software (v 5.2), while the analysis on FACSCanto was done using FACSCanto (v 1.0.3) and FACSDiva (v 4.1) softwares respectively. RESULTS: The data shows significantly higher mean CD3 T-cell counts on FACSCalibur, Cell Quest Pro (1,864 +/- 1,044 cells/microl) as compared to FACSCanto (1,840 +/- 1,040 cells/microl) (P < 0.05). The CD4 T-cell counts were also higher on FACSCalibur, Cell Quest Pro (885 +/- 770 cells/microl), and FACSDiva (892 +/- 773 cells/microl) versus FACSCanto (867 +/- 767 cells/microl) (P < 0.05). FACSCalibur, Cell Quest Pro, and FACSDiva showed similar values except for CD8 T-lymphocytes where FACSDiva had significantly lower values (P < 0.05). The B-cell counts were unaffected when either of the instruments or softwares were used, while the natural killer (NK) cells (CD16 + 56 positive cells) showed similar trend like CD3 and CD4 counts with significant differences in the mean cell counts between FACSCalibur, Cell Quest Pro (240 +/- 165 cells/microl), and FACSDiva (238 +/- 163 cells/microl) versus FACSCanto with higher NK cell counts (260 +/- 176 cells/microl). CONCLUSIONS: The enumeration of lymphocyte subsets was comparable between FACSCalibur, Cell Quest Pro, and FACSDiva, based analysis and it was significantly different than FACSCanto software based analysis. Our observations suggest that FACSDiva software should be preferred over the FACSCanto software for immunophenotyping on FACSCanto flow cytometer and the laboratories should report the instrument and software used for the specimen analysis while reporting immunophenotyping results.

Radiation-pressure-based cylindrically shaped microactuator capable of smooth, continuous, reversible, and stepped rotation.

Long cylindrical objects have been observed to align their central axis with the propagation axis of the illuminating laser beam through the action of radiation-pressure-generated force and torque. A cylindrically shaped microactuator based on this principle and suitable for micromachine applications is examined theoretically. When four in-plane laser beams converging at a common point centered on the cylinder are used, the cylinder can be made to rotate about a pivot point. In one mode, smooth, continuous, and reversible rotation is possible, whereas the other cylinder can be step rotated and locked, similar to the operation of conventional stepping motors. The properties of the device are analyzed based on obtaining either a constant rotation rate with variable beam power levels or a quasi-constant rotation rate with constant beam power levels or on using a fixed beam sequence rate that matches the system parameters and produces smooth or stepped operation.

Experimental confirmation of the optical-trapping properties of cylindrical objects.

A sophisticated modeling program was used recently to predict the trapping and the manipulation properties of elongated cylindrical objects in the focal region of a high-intensity laser beam. On the basis of the model, the cylinders should align their longest diagonal dimension with the propagation axis of the laser beam and follow the beam when it is displaced transverse to the cylinder's central axis. Experimental confirmation of the cylinder's behavior is presented and confirms the suitability of the enhanced ray-optics approach to modeling micrometer-scale objects in optical-trap environments.

Simulated dynamic behavior of single and multiple spheres in the trap region of focused laser beams.

An enhanced photon propagation method is used to calculate the forces and torque present on each sphere of a system of particles located in the vicinity of focused laser-trapping beams. Infinitesimal trajectory displacements are computed through classical mechanics and the new particle position used to define the next trapping system geometry considered. Repeated applications of the process, implemented as a computer program, enables full trajectory plotting and the dynamic behavior of the systems to be explored as a function of time.

Hearing acuity of anesthesiologists and alarm detection.

BACKGROUND: With rapid technological advances in anesthesiology, we are acquiring an ever increasing number of auditory alarm systems in the operating room the value of which depend on the hearing acuity of the anesthesiologist monitoring the patient. Presbycusis, the effect of aging on the auditory system, characteristically results in a bilaterally symmetric neurosensory high-frequency hearing loss ( > 2,000 Hz). In this study we attempt to assess the impact of this common hearing disorder on alarm detection. METHODS: We measured air conduction hearing acuities of 188 anesthesiologists who volunteered to participate. Subjects were divided into six age groups (25-34, 35-44, 45-54, 55-64, and > 75 yr of age). Abnormal audiograms were compared to the intensity and frequency of alarms in our operating room to determine which alarms were out of hearing range. Subjects with a history of chronic or excessive noise exposure were excluded from the study. The median hearing threshold for each age group of study subjects was compared to the median hearing threshold of similar age groups in the general population. RESULTS: Overall, 66% of the subjects had an abnormal audiogram, and 7% had one or more alarm intensities less than their detectability threshold (14% unilateral, 86% bilateral). Median hearing threshold was worse than the general population for men and women less than 55 yr of age. Hearing acuity worse than the general population occurred at the lower frequencies while acuity at the higher frequencies was equal or slightly better. However, inability to hear alarms occurred only with those alarms that have frequencies of 4,000 Hz or greater. CONCLUSIONS: Although high-frequency hearing acuity of individuals in our study was better than that of the general population, hearing deficits at high frequencies were of the magnitude to interfere with alarm detection. Also background noise levels vary greatly in different operating rooms. These two problems create a hindrance to alarm detection for certain anesthesiologists. From our data we conclude that the aging human ear may not be capable of accurately detecting some auditory alarms in the operating room. Alarm design should consider hearing acuity because high-frequency alarms may go undetected.

Use of whole blood methods in assessment of immune parameters in immunodeficiency states.

Whole blood (WB) methods requiring less than 4 ml heparinized peripheral blood were used to define mononuclear cell phenotype, lymphocyte proliferation, and natural cell-mediated cytotoxicity (CYT) in samples from normal controls and patients with immunodeficiency states of acquired immunodeficiency syndrome (AIDS) and AIDS-related complexes (ARC). Results from two-color direct immunofluorescence staining of blood samples with monoclonal antibodies (Mabs) conjugated to phycoerythrin (PE) or to fluorescein isothiocyanate (FITC) and flow cytometry for the determination of mononuclear cells reactive with T11, T4, T8, B1, and NKH.1 surface markers were compared to one-color indirect immunofluorescence analysis with unlabeled Mabs and FITC-labeled goat anti-mouse IgG and flow cytometry. We found that two-color analysis was as sensitive as one-color analysis in detecting abnormal subset distribution in the patient groups. Functional properties of mononuclear cells (MNC) in WB samples and after density gradient separation were studied by mitogen-induced lymphocyte proliferation and CYT. Although the means of the groups studied varied depending on method used, results using WB methods clearly delineated the expected differences between the immunodepressed patients and normal subjects. The effects of sample storage on results obtained with WB methods for surface marker analysis, lymphocyte proliferation, and natural killer activity were also examined.

Doxorubicin, cyclophosphamide, and whole body hyperthermia for treatment of advanced soft tissue sarcoma.

Eleven patients with advanced soft tissue sarcoma were treated with whole body hyperthermia (41.8 degrees C-43.0 degrees C) for 2 hours, doxorubicin (45 mg/m2) at the beginning of peak temperature and cyclophosphamide (1000 mg/m2) 6 hours after doxorubicin. Warming was accomplished with a nylon and vinyl mesh water perfused suit and heating blankets under barbiturate anesthesia. Thirty-five thermochemotherapy treatments were administered after an initial baseline euthermic course. There were two complete and two partial responses including three of three liposarcomas and one of two leiomyosarcomas, and there were two disease stabilizations . Morbidity included anasarca, nausea and vomiting, diarrhea, myalgias, mild surface burns, perioral herpes simplex, reversible neuropathy, hypotension, and cardiac arrythmias . Hyperglycemia and hypophosphatemia were found during heating, and normalized at 24 hours. Liver enzyme elevations occurred 24 hours after heating and normalized within 1 week. A uniform platelet decrease (mean, 107,000/microliter) was found at 24 hours. Thermochemotherapy was found to be a feasible approach for selected patients with advanced soft tissue sarcoma for the subset of liposarcomas and leiomyosarcomas.